However we must stand out that this extinguishing was not given of automatic form, but after a period called ' ' resistance to extino' ' , characterized for the number of times that continued having reply emission, exactly after the suspension of the reinforcement. The comment of other effect of the process of operative extinguishing was possible still, namely: increase in the frequency of reply at the beginning of the process, greater variety of the forms of reply presented and the appearance of considered answers emotional, as anxiety and anger. Finally, the intended behavior, strengthening of differentiated form was shaped the answers that more were come close to the cited behavior. In a posterior stage, we carry through new extinguishing, that if it showed more difficult, with the animal presenting a bigger time of resistance to stop of if holding. Method and Result the experiment was carried through in the laboratory of Experimental Psychology of the College Loved Jorge. For such, a white rat proceeding from the laboratory of Experimental Psychology was used in order to have its behavior studied for pair of students of 2 semester of the nocturnal turn of the course of Psychology. During all the experiment the rat remained in the interior of the box of Skinner, instrument chosen for the application of the necessary techniques to the study. The practical ones were made a time per week and the practical initial had the objective to collect given of the behavior without the job of no arbitrary stimulaton. In such a way, we know the behavior of the animal in its state ' ' natural' ' (incondicionados elaboration of the base line, behaviors) to serve as parameter subsequent to the introduction of the conditioning techniques. Inside of the box of Skinner, during 30 minutes, we register (to each 3 seconds) the frequency with that the rat if held of the following forms: to farejar, to raise, to clean themselves, to touch the bar, to be stopped and pressuring the bar (behavior-target, still unknown for the stimulaton ' ' to drink gua' ').